A diagram of the principle of such screens and the way of addressing them is given in the following article to which reference is to be made:
T. LEROUX and al and entitled "Microtips Displays Addressing" SID 91 , p. 437
Moreover, this article indicates the main two drawbacks of these screens which are due to:
the use of high line voltages incurring high costs for line scanning circuits, and PA1 the high line/column capacity due to the structure of these screens. PA1 first parallel electrodes known as lines playing the role of grids electrically isolated from the columns and forming an angle with the latter, and PA1 line control means provided so as to have the potential of the latter evolve up to a positive value Vl, said screen being characterized in that it further includes: PA1 at least one additional electrode known as a zeroized column parallel to the columns and common to all the lines and also forming a cathodic conductor able to emit electrons, PA1 means for controlling this zeroized column and able to bring the latter to a negative potential so that, irrespective of the potential of the lines this zeroized column crosses, electrons may be emitted in the crossing zones, PA1 at least one additional anode known as a control anode and placed opposite the zeroized column, and PA1 means for polarizing this control anode and able to bring the latter to a potential Vac lower than Vl, and wherein the line control means include for each line a single output transistor provided to bring the corresponding line to the potential Vc when this transistor is activated and to disconnect this line from the voltage source Vl when this transistor is disactivated.
Given the fact that on each line this capacity may be loaded and unloaded at the control voltage of the columns Vc, the resultant consumption is given by the following formula: EQU W=C.times.Vc.sup.2 .times.Fl
where W is the consumption per dm.sup.2, C is the capacity per dm.sup.2 (about 30 pF/mm.sup.2), Vc is the column control voltage (modulation voltage of the column signals, namely about between 30 and 40 V), and Fl is the line scanning frequency (Tl=1/Fl is the selection time of one line and Fl is between 15 and 30 kHz).
Having regard to the values given above, this consumption W may reach about between 5 and 15 W/dm.sup.2.